i have noticed many of the mp3s i download from archive.org (Creative Commons) go above the 1.0 Track Peak according Replay Gain, however i have not been able to notice this in other formats. when rendering audio losslessly it clips, why/is mp3 an exception?

i have noticed many of the mp3s i download from archive.org (Creative Commons) go above the 1.0 Track Peak according Replay Gain, however i have not been able to notice this in other formats. when rendering audio losslessly it clips, why/is mp3 an exception?